Identification of hazelnut varieties.

Most varieties covered by this guide have been listed for sale in nursery catalogues over the last 20 years and are most likely to be present in orchards planted over that period. Owners of older plantings may have varieties that have not been offered for sale recently. If these older varieties or NZ selections are present in the collections at Wairata Forest Farm or Lincoln University, brief descriptions can be found in the report “The Identification of Hazelnut Varieties available in New Zealand” (see Resources).

The characteristics of a variety’s nuts will usually allow growers to identify varieties commonly available in New Zealand. While it is possible for seedlings to have nuts that are similar to those of the parent, it is rare for all other characteristics (time of pollen shedding, flowering, bud characteristics, tree shape) to also be identical.

Identification should start with nut characteristics to identify varieties. Once a probable variety has been selected, the winter flowering and bud characteristics can be used to confirm the identification.  Any plants that do not fit all the listed characteristics are likely to be seedlings.

 

The nut characteristics listed on Table 1 allow a grower with a nut sample to move through a few key characteristics, starting with the shape, to a probable variety.  Clicking on the variety name will access a description and photographs of nuts, green nut clusters, buds and catkins of that variety.

In the photographs of the nut characteristics, blanched kernels are shown on the right hand side of the photographs. Mostly these will show some white blanched areas, but kernels that do not blanch will appear identical to the unblanched kernels adjacent.

 

Table 2 covers the physical characteristics of the tree that can be observed during the winter and early spring. This table will be useful for nurseries that are dealing with mother beds or young trees that are not cropping, and as confirmation for growers who may suspect that they may have seedlings rather than named varieties.

 

Most terms used in this guide follow those prescribed in “Descriptors for Hazelnut (Corylus avellana L.)” (Bioversity, FAO, and CIHEAM. 2008). This publication is available online at www.bioversityinternational.org.

Definitions of nut size and catkin size were not included in the above publication and have been defined below.

The nut characteristics of the varieties are defined using nuts from well grown mature trees in good growing climates. Some nut characteristics may differ when using nuts from trees in less suitable growing situations. For example, unpruned shaded trees or trees under moisture stress will often have a high proportion of shrivelled kernels or more fibre than normal. Mould and heavy fibre cover are more prevalent in damp seasons.

Bud and catkin characteristics are taken from vigorous growths on the outside of the canopy

 

Definitions of the Nut Characteristics in Table 1:

Shape:

The six nut shapes are illustrated in Fig. 1 with a simple description of the terms given below.

Key	Shape	Description	Reference cultivar(s)
1:	Oblate:	length is less than the width, a “flat” nut	Imperiale de Trebizonde
2:	Globular:	length is about the same as width, a “round” nut	Barcelona, Tonda Gentile delle Langhe
3:	Conical:	length is greater than the width; cone shaped	Merveille de Bollwiller
4:	Ovoid:	length is greater than the width; oval shaped	Negret
5:	Short subcylindrical:	a slightly elongated nut	Butler
6:	Long subcylindrical:	a long nut	Kentish Cob

 

Length:	Average of at least 25 nuts, measured from the most distant points along the main seed axis.
Width:	average of at least 25 nuts, measured from the widest point perpendicular to the main seed axis.
Thickness:	average of at least 25 nuts, measured at the widest point perpendicular to the suture.

Size:

Size is based on the average width of at least 25 nuts.

Large:	Greater then 20mm, the diameter of a 10 cent coin.
Medium:	13 to 20 mm.
Small:	Less than 13mm.

Shell colour:

This is the colour of the shell of freshly harvested nuts. Nut colour darkens as the nut dries.

Reference varieties are:

Light brown:	Butler, Ennis.
Brown:	Barcelona, Tonda Romana, Tonda di Giffoni.
Dark brown:	Negret (similar to Appleby).

Dull, pale nuts, such as Alexandra, often have creamy pale shells when fresh, sometimes with hints of green shell. They dry to a pale brown.

Shell Striping:

Striping refers to the darker coloured stripes running down the smooth shell. This is distinct from the striping effect caused by the ribbed or corrugated surface of the shell.

Ribbed shells are a distinctive feature of some varieties.

Kernel fibre:

Kernel fibre is the rough corky material adhering to the pellicle (the smooth brown skin on the kernel).

Blanching:

Blanching assesses the amount of pellicle removal after 20 minutes in an oven at 115°C (Thompson et. al. 1978 – see Reference).

None:	No pellicle removal.
Poor:	Less than 50% pellicle removal.
Medium:	50 – 75% pellicle removal.
Good:	75 – 90% pellicle removal.
Excellent:	More than 90% pellicle removal.

 

Table 1: Nut characteristics

Shape	Size	Shell Colour	Shell Striping	Kernel Fibre	Kernel Blanching	Variety
Oblate	medium	brown	few	medium	excellent	Nocchione
Globular – obl	medium	brown	medium	light	poor	Tonda Romana
Globular – obl	medium	brown	many	light	excellent	Tonda di Giffoni
Globular – obl	large	brown	med, corr	light	poor	Lansing
Globular	large	light brown	many, corr	none	poor	OSU 18-114
Globular	large	dull, pale	few	none	none	Plowright
Globular	large	light brown	many	light	medium	OSU 14-84
Globular	large	light brown	many	medium	excellent	Campanica
Globular	large	brown	absent	medium	medium	Barcelona
Globular	medium	brown	few	light	excellent	Whiteheart
Globular	sm – med	light brown	few	medium	excellent	TGDL
Conical	large	brown	few	none	good	M. de Bollwiller
Ovoid	large	light brown	many	none	none	Ennis
Ovoid	large	light brown	few	none	good	Royal
Ovoid	medium	dull, pale	few, corr	high	excellent	Gisborne
Ovoid	med-small	dark brown	absent	light	excellent	Appleby
Sht. subcylind.	large	light brown	medium	light	poor	Butler
Sht. subcylind.	med-large	dull, pale	few, corr	medium	poor	Alexandra
Sht. subcylind.	med-large	brown	few	light	good	San Giovanni
Long subcyl.	med-large	brown	medium	light	none	Kentish Cob
Long subcyl.	med-large	brown	few, corr	none	none	Keen’s Late
Long subcyl.	med-small	brown	few	none	good	Nott/Wisp/WSF

Abbreviations: Obl. = oblate; Sht. = short; subcyl. = subcylindrical; sm = small;
med = medium; corr = corrugated shell surface; TGDL = Tonda Gentile delle Langhe;
Nott. = Nottingham; Wisp. = Wispit; WSF = White Skinned Filbert.

 

Definitions of the winter flowering/bud characteristics in Table 2

Relative dates of pollen shed and female flowering.

The dates of these characteristics are dependent on the seasonal temperature characteristics and can change from season to season and differ between regions. However, the relative timing for these events for different varieties is usually reasonably constant (Thompson et al, 1978 – see Reference).

Information on timing in southern growing areas is limited for varieties other than Whiteheart and its pollinisers so the information for this table is based on averaged values from the Wairata Forest Farm hazel collection. Comparisons with flowering records from Otago and Canterbury over the 2010 season indicate that this information will be applicable to most of New Zealand.

Merveille de Bollwiller is a variety with very distinctive characteristics that is present in most plantings and is used here as a reference variety. Merveille de Bollwiller sheds pollen late, flowers late, and leaves emerge late.

In most parts of New Zealand, June would be considered early for pollen shedding and flowering, July would be mid-season, August is late and September is very late.

Relative time of bud burst.

Calendar dates, collected from the Wairata Forest Farm collection and averaged over the last seven years of data; illustrate the date of bud burst relative to Merveille de Bollwiller.

Relative time of budburst	Calendar dates	Reference variety
Very early	Early August	Tonda di Giffoni
Early	Late August	Lansing
Intermediate	Early September	Barcelona
Late	Late September	Merveille de Bollwiller
Very late	October	Alexandra

 

Catkin Size.

Catkin length:	Long:	most greater than 25 mm long
	Short:	most less than 25 mm long
Catkin thickness:	thin:	most 4 to 5 mm thick.
	medium:	most 5 to 6 mm thick.
	thick:	most 6 mm or thicker.

 

Bud shape and colour.

These are typical buds on vigorous growth in mid-winter.

Reference varieties for bud shape are:

Globular:	Whiteheart, Kentish Cob.
Ovoid:	Barcelona
Pointed:	Merveille de Bollwiller

Usually buds have varying degrees of green background colour.
The listed colour is the dominant overlying colour.

 

Table 2: Winter flowering and bud characteristics

Relative date of pollen shed	Relative date of female flowering	Relative time of bud burst	Catkin size	Bud shape and colour	Variety
Very early	midseason	Very early	Long, medium	Green, globular	TGDL
Very early	midseason	early	Long, medium	Green, globular	Royal
Very early	late	intermediate	Short, medium	Bn/gn, ovoid	Butler
Early	midseason	intermediate	Short, medium	Brown, globular	Appleby
Early	Very early	Very early	Long, medium	Green, globular	San Giovanni
Early	early	early	Short, thin	Bn/gn, globular	Campanica
Early	early	early	Short, thin	Green, globular	Nocchione
Early	Mid – late	intermediate	Long, medium	Bn/gn, ovoid	Barcelona
Early – mid	Early – mid	Very early	Short, thin	Bn/gn, globular	Tonda di Giffoni
Early – mid	Early – mid	Early	Long, medium	Green, ovoid	Lansing
Early – mid	midseason	intermediate	Short, medium	Bn/gn, globular	Tonda Romana
Early – mid	Mid – late	intermediate	Short, medium	Red/gn, pointed	OSU 14-84
Midseason	midseason	Very early	Long, medium	Red/gn, ovoid	Gisborne
Midseason	Mid – late	late	Short, medium	Bn/gn, ovoid	OSU 18-114
Mid season	Late – very late	late	Short, medium	Bn/gn, ovoid	Ennis
Midseason	Late – very late	intermediate	Long, thick	Bn/gn, globular	Whiteheart
Late	Late	Late	Long, medium	Red, pointed	M. de Bollwiller
Late	Late	Late	Short, thin	Bn/gn, globular	Plowright
Late	Very late	Very late	Long, thick	Red/gn, conical	Alexandra
Late	Late	Late	Long, medium	Bn/gn, ovoid	Kentish Cob
Very Late	Late	Very Late	Long, medium	Bn/gn, globular	Keen’s Late

 

Abbreviations: Mid. = midseason; Bn. = brown; gn. = green; TGDL = Tonda Gentile delle Langhe; M. de Bollwiller = Merveille de Bollwiller.

 

Next page – Variety Index